Campus alerting via wireless geocast

ABSTRACT

A geocast alerting system employs wireless geocast transmissions to deliver customized alerting messages to particular geographic areas. Geocast alerting regions and sub-regions can be defined within the system. Upon notice of the occurrence of an emergent situation, one or more geographic areas that may potentially be affected by the emergent situation are determined. The potentially effected geographic regions are compared with geocast alerting regions and sub-regions corresponding to particular geographic areas. Target alerting regions that should receive alerting messages are identified based on the comparison. The content of alerting messages can be tailored for each target alerting region. The content of alerting messages can contain distinct portions of content, each portion tailored based upon one or more conditions related to communications devices within the target alerting region.

CROSS REFERENCE TO RELATED APPLICATIONS

The instant application is a continuation application of, and claimspriority to, U.S. patent application Ser. No. 13/890,423, filed May 9,2013. U.S. patent application Ser. No. 13/890,423 is a continuation of,and claims priority to, U.S. patent application Ser. No. 12/643,346,filed Dec. 21, 2009, which issued on Jul. 9, 2013, with U.S. Pat. No.8,483,652. U.S. patent application Ser. No. 12/643,346 claims priorityto U.S. provisional patent application No. 61/258,167, filed Nov. 4,2009. U.S. patent application Ser. No. 13/890,423 is incorporated hereinby reference in its entirety. U.S. patent application Ser. No.12/643,346 is incorporated herein by reference in its entirety. U.S.provisional patent application No. 61/258,167 is incorporated herein byreference in its entirety. U.S. Pat. No. 8,483,652 is incorporatedherein by reference in its entirety.

BACKGROUND

Typical approaches to alerting individuals in a particular geographicarea, for example campus alerting at a college or university, involvesending generic broadcast alerting messages pertaining to an emergentsituation. For example, a broadcast message might be sent to allsubscribers to a campus alerting system. Such a message might containgeneric information or instructions pertaining to an emergent situationtaking place somewhere on the campus. This type of alerting, however,has several shortcomings. For example, in a campus alerting scenario,the alerting message may not reach all persons who may be affected, suchas visitors, attendees at a campus sporting event, or othernon-subscribers. Further, sending a generic message to all subscribersmay cause needless panic, for example alerting subscribers at a crowdedsporting event when the emergent situation is occurring in a remote areadistant from the sports stadium. Delivering a generic message might alsoput innocents in harm's way, for example if an alerting messagedescribing an escape route was delivered to a terrorist holdinghostages, thereby facilitating cutoff of the escape route. Additionally,broadcast alerting systems are costly, both in terms of the overheadinvolved in maintaining lists of subscribers, and in terms of thenetwork resources consumed. Large scale broadcasts may overburdennetwork components, resulting in failed delivery or message loss.

SUMMARY

Wireless geocast alerting allows delivery of customized alertingmessages to particular geographic areas. Alerting messages can bedelivered to ad hoc networks of mobile devices within particulargeographic areas via a geocast transmission protocol. Such ad hoc mobilenetworks are distributed and scalable, enabling alerting messages topropagate between mobile communications devices without the use oftraditional network components. Pre-subscription to an alerting serviceis not required, thereby eliminating the concern that some individualswill not receive alerting messages. Alerting messages can be transmittedto particular geographic areas, and can contain distinct messagingcontent appropriate to each particular area (e.g., information and/orinstructions), thereby mitigating the chances of creating unnecessarypanic and/or alerting individuals who should not receive alertingmessages. The content of alerting messages can also be made up ofdistinct portions of content. Each portion of content can be tailoredbased on one or more conditions. Subsequent alerting messages containingupdates may be provided as an emergent situation changes with time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1E depict example techniques that may be used for defining theshape and/or dimensions of geocast alerting regions.

FIG. 2 illustrates communication in an ad hoc network via WiFi accesspoints.

FIG. 3 illustrates tiered geocasting and forwarding zones.

FIG. 4 is a flow diagram depicting an example process for providing analerting message, or the like, via geocasting.

FIG. 5 depicts an example of providing customized alerting messages viageocast alerting.

FIG. 6 is a block diagram of an example communications device configuredto communicate in an ad hoc network of communications devices inaccordance with a scalable wireless geocast protocol.

FIG. 7 depicts an example packet-based mobile cellular networkenvironment, such as a GPRS network, in which communications in an adhoc network of communications devices in accordance with a scalablewireless geocast protocol can be implemented.

FIG. 8 depicts an example architecture of a typical GPRS network inwhich communications in an ad hoc network of communications devices inaccordance with a scalable wireless geocast protocol can be implemented.

FIG. 9 depicts an example GSM/GPRS/IP multimedia network architecturewithin which communications in an ad hoc network of communicationsdevices in accordance with a scalable wireless geocast protocol can beimplemented.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Customized alerting information may be received and rendered by a mobilecommunications device based on the location of the mobile device and/ora condition associated with the mobile device, for example whether thedevice is stationary or moving, and if moving, the direction and/orspeed of movement. For example, alerting messages containing specificwarnings and/or instructions can be delivered to mobile communicationsdevices located in the immediate geographic area of an emergentsituation, while different alerting messages and/or instructions can bedelivered to mobile communications devices at nearby geographiclocations where the mobile device operators are not in imminent danger.Alerting message content may be further distinguished based on acondition of a mobile communications device. For example, the alertingmessage content rendered by a mobile communications device may depend ona direction of movement (e.g., towards or away from the danger area),and the speed at which the communications device is moving. Subsequentalerting messages specific to different geocast alerting regions may betransmitted based on trends or developments in the emergent situationover time. Geocast alerting regions may be predefined, but can also bedetermined dynamically or in real-time. Boundaries of geocast alertingregions may be defined via automatic or user-driven processes, or acombination thereof.

In the embodiments described herein, customized alerting messages may beprovided to mobile devices in distinct geographic areas via geographicalbroadcasting, referred to as geocasting. Geocasting is described in U.S.Pat. No. 7,525,933, entitled “System And Method For Mobile Ad HocNetwork,” filed Nov. 30, 2005, issued Apr. 28, 2009, which isincorporated by reference herein in its entirety. Geocasting uses aprotocol in which an IP address is replaced with a geographic address.Generally, geocast alerting message packets are sent to every mobilecommunications device located within a specific geocast alerting region.A geocast alerting region generally corresponds to a specific geographicarea. Each geocast alerting message packet may contain an indication ofa destination geocast region for the alerting message and alertingmessage content. A geocast alerting message packet may also contain anindication of the location of the sender of the alerting message. Mobilecommunication devices participating in geocast messaging may be referredto collectively as a geocast ad hoc network. No registration is requiredfor a mobile communications device to join a geocast ad hoc network. Asmobile communications devices move within communications range ofmembers of a geocast ad hoc network, they can automatically participatein the geocast ad hoc network. The mobile communication devices of an adhoc network communicate with each other, and each mobile communicationsdevice in the ad hoc network is capable of receiving and/or transmittinggeocast alerting message packets to and/or from other communicationsdevices in the ad hoc network of mobile communications devices. Ad hocnetworks of mobile communication devices do not require base stationterminals or other network components to facilitate or controlcommunications between the mobile communications devices. However, insome embodiments, base stations and/or other network components may beused to relay and/or bridge geocast messages between geocast ad hocnetworks or between geocast ad hoc networks and other networks, forexample the Internet.

A mobile communications device that receives geocast packets mayredistribute the geocast packets to other mobile communications devicesaccording to heuristic decision rules that determine whether a receivingcommunications device will re-transmit a received packet. These ruleseffectively guide geocast packets to their destinations and controlcommunication traffic within the ad hoc network. The decision rulesachieve this control by using statistics obtained and recorded by thecommunications device as it receives packets transmitted within itsreception range. This distributed packet transfer mechanism results ingeocast packets “flowing” to and throughout the geocast region specifiedin each geocast packet. The communications devices in the geocast regionreceive and process each distinct geocast packet, and may render thecontent of the geocast packet to the user via a user interface of thecommunications device. Two geocast packets are distinct if they containdistinct geocast identifiers. However, a retransmitted copy of a packetgenerally will contain the same geocast identifier as the originalpacket.

In an example embodiment applying heuristic decision rules, a receivingcommunications device may determine whether to retransmit a geocastmessage packet based upon the number of times the geocast message waspreviously received, the communication device's proximity with respectto the communications devices from which the message was sent, and/orthe communication device's proximity to the geocast region. Thisdecision process may be implemented as a three step location-basedapproach, which is described in detail in the aforementioned U.S. Pat.No. 7,525,933, entitled “System And Method For Mobile Ad Hoc Network,”filed Nov. 30, 2005, issued Apr. 28, 2009. In a first step of thelocation-based approach, the receiving communications device determineswhether it has previously received the same geocast message at least apredetermined number (N) of times. If not, it retransmits the messageover the ad hoc network of communications devices. If so, thecommunications device progresses to the second step and determineswhether the sending communications device is closer than some minimumdistance away. If no prior sender of the geocast message was closer thanthe minimum distance away, the communications device retransmits thegeocast message to the ad hoc network of communications devices.Otherwise, the communications device progresses to the third step anddetermines whether it is closer to the center of the geocast region thanany sending communications device from which the geocast message wasreceived. If so, the communications device transmits the geocast messageover the ad hoc network of communications devices. If not, thecommunications device does not retransmit the geocast message.

This location-based approach prevents a receiving communications devicefrom retransmitting a geocast message that was most likely alreadyretransmitted by another communications device located close to it (andthus most likely reaching the same neighboring communications devicesthat it can reach). In addition, this location-based approach reducesthe chance that the communications device will retransmit the samegeocast message multiple times to the same neighboring communicationsdevices.

While transmission and propagation of alerting messages are describedherein with reference to embodiments using a particular scalablewireless geocast protocol, the scope of the instant disclosure shouldnot be limited thereto. It is to be understood that the methods andapparatuses for distributing alerting messages as described herein maybe implemented in conjunction with other geographic broadcast protocols,and that the use of such other geographic broadcast protocols is meantto be included within the scope of the instant disclosure.

FIGS. 1A-1E depict example techniques for defining geocast regions. Ageocast region may be defined to be a single point 102, as depicted inFIG. 1A. A point geocast region may be defined by a longitude value anda latitude value (not shown). A point above the surface of the earthcould be defined by providing an altitude value in addition to longitudeand latitude values. A geocast region may also be comprised of multiplesingle points (not shown) such as the single point 102. Location pointssuch as point 102 may be used as the building blocks for more complexgeocast region geometries, as described herein. FIG. 1B depicts ageocast region defined by a point 102 in combination with a radius 104.The geocast region of this example will comprise the area enclosed bythe radius, and may include the space above the area as well. A geocastregion could also be defined as the overlap region between two or morecircular geocast regions (not shown). FIG. 1C depicts a more complexgeometry formed from a series of points 102 interconnected with straightboundary lines. This technique of geocast region definition is similarto the techniques typically used in the definition of parcels of realproperty. FIGS. 1D and 1E depict the creation of one or more geocastregions within a single geographic footprint. FIG. 1D depicts creating ageocast region for a specific floor of a building 106. The single floorgeocast region is defined as the volume of space between upper and lowerareas, each formed using a series of points 102 set at corners of thebuildings. FIG. 1E depicts an alternate technique for defining a singlefloor geocast region in building 106. Upper and lower points 102 aredefined in the middle of the ceiling and the floor of the geocast regionrespectively. The single floor geocast region is then defined as thevolume of space between an upper area and a lower area defined by a pairof radii 104 extending from the middle points. Geocast regions may alsobe defined to change in size, geographic location, etc. with time (notshown), essentially allowing the creation of geocast alerting regions infour dimensions. For example a geocast alerting region corresponding toa dangerous weather system may be defined to change size, shape, and/orgeographic location to provide location specific geocast alertingmessages as the weather moves over time. Information defining aparticular geocast region (e.g., a series of points) can be communicatedin an addressing portion of a geocast alerting message. Geocastsub-regions may be defined within a particular geocast region using theabove techniques. It should be noted that the techniques described withreference to FIGS. 1A-1E are merely examples, and the scope of theinstant disclosure should not be limited thereto. Other alerting regiongeometries and techniques for defining geocast alerting regions may berecognized by those skilled in the art, and are meant to be includedwithin the scope of the instant disclosure.

FIG. 2 illustrates communication in an ad hoc network of communicationsdevices via WiFi access points 200 and 202. Communications devices in ageocast ad hoc network can communicate via RF signals encoded withgeographic information, via Bluetooth® technology, via WiFi (e.g., inaccordance with the 802.11 standard), or the like, or any combinationthereof. For example, as depicted in FIG. 2, mobile communicationsdevices 204, 206, 208, 210, and 212 form one geocast ad hoc network andmobile communications devices 214 and 216 form another geocast ad hocnetwork. Coverage area 218, which is the area covered by the WiFi accesspoint 200, covers the mobile communication devices 204 and 206. Coveragearea 220, which is the area covered by the WiFi access point 202, coversthe mobile communication device 214. As shown in FIG. 2, the mobilecommunications device 216 transmits to the mobile communications device214 directly (e.g., via Bluetooth®). The mobile communications device214 retransmits to the WiFi access point 202, which in turn retransmitsto the WiFi access point 200 over a network, for example the Internet.The mobile communications devices 204 and 206 receive the transmissionfrom the WiFi access point 200, and the mobile communications device 206retransmits directly to the mobile communications device 208. And, asdepicted, the mobile communications device 208 retransmits to the mobilecommunications devices 210 and 212.

FIG. 3 illustrates tiered geocasting and forwarding zones. Tieredgeocasting extends the reach of ad hoc communication networks throughthe use of long range transmitters (such as communications devices,etc.), infrastructure, a communications network, a cellular tower, or acombination thereof, when available. Tiered geocasting may enablegeocast alerting messages to be transmitted between mobilecommunications devices separated by distances beyond the broadcast rangeof typical mobile communications devices. Tiered geocasting assumes thatat least one communications device within an ad hoc network is capableof communicating via a long range tier 300. A long range tier is a termindicating a tier wherein characteristic message transfers betweendevices occur over a longer physical range than those over some othertier, such as a short range tier 302. A long range tier can be wireless,wired, or a combination thereof.

A forwarding zone can be utilized to implement tiered geocasting. Acommon forwarding zone can be defined for all geocast packets ordifferent forwarding zones can be defined for different types of geocastpackets. Forwarding zones (as depicted in FIG. 3 by short and long rangeforwarding zones 334 and 336 respectively, for example and withoutlimitation) can be defined differently in different tiers for a singlepacket type, or even on a packet by packet basis. Thus, forwardingheuristics can be applied independently per tier, with bridging atmulti-tier capable nodes. In an example embodiment, a communicationsdevice retransmits a packet only if the communications device is locatedwithin the forwarding zone defined for the packet's type. Thisdetermination is in addition to the determinations described above and,if the communications device is not in the forwarding zone, the packetwill not be retransmitted, even if one or more of the above conditionswould otherwise have caused a retransmission hold.

As depicted in FIG. 3, nodes (e.g., communications devices) 304, 306,308, 310, 312, 314, and 316, are at various locations within the shortrange tier 302 and the long range tier 300. All of communicationsdevices 304, 306, 308, 310, 312, 314, and 316 together form a geocast adhoc network. The communications devices 312, 314, and 316 are located ingeocast region 318. In an example embodiment, the communications device304 may transmit a geocast message with a destination address of thegeocast region 318. Each of the communications devices 304, 306, 308,310, 312, 314, and 316 can determine its own geographic location throughany type of location determination system including, for example, theglobal positioning system (GPS), assisted GPS (A-GPS), time differenceof arrival calculations, configured constant location (in the case ofnon-moving nodes), any combination thereof, or any other appropriatemeans. Each communications device is operable to transmit and receivegeocast packets via the geocast ad hoc network. In addition, at anygiven time, some subset (possibly all) of the communications devices maybe operable to transmit and receive geocast packets over the long rangetier 300 network. For example, though not a limitation, in FIG. 3, thecommunications devices 306, 308, and 310 can transmit and receivegeocast messages over both the short range tier 302 and the long rangetier 300. Note that this latter fact is indicated visually in thediagram by the communications devices 306, 308, and 310 each beingrepresented by two nodes (one in the short range tier and one in thelong range tier) connected by a vertical line. The long-range tier 300network can be any network in which packets can be transmitted from onelong range capable communications device to another long range capablecommunications device. Such packet networks can include, for example, aninfrastructure-based network comprising wireless base stations (for up-and down-link) operating on a separate frequency from that used by thead hoc network. In addition, the long rang tier network also could beimplemented simply as another instance of an ad hoc communicationsnetwork using distinct radio frequencies and possibly longer radioranges.

The communications device 304 transmits, within its communication range320, a geocast message addressed to the geocast region 318, and thecommunications device 306, located within the communications range 320of the communications device 304, receives the transmission. Thecommunications device 306 may retransmit the message, within itscommunications range 322 on the short range tier 302, in accordance withthe heuristics for the short range forwarding zone 334. Thecommunications device 306, with long range transmission capability (inthe long range tier 300), may simultaneously retransmit the messagewithin its communication range 324 on the long range tier 300. Thecommunications device 308, configured for long range communications onlyand located within the communications range 324 of the communicationsdevice 306, receives the transmission from the communications device 306and may retransmit the message within its communication range 326 on thelong range tier 300. The communications device 310, located within thecommunication range 326 of the communications device 308, receives thetransmission from the communications device 308 and may retransmit themessage in both its communication range 328 on the long range tier andits communication range 330 on the short range tier. The communicationsdevice 312, a member of the geocast region 318 and located within thecommunication range 330 of the communications device 310, receives thetransmission from the communications device 310 and may retransmit themessage within its communication range 332 on the short range tier, thustransmitting the geocast message to the communications devices 314 and316, the other members of geocast region 318, thereby completing thegeocast message transmission.

FIG. 4 is a flow diagram 400 of an example process for providing analerting message, or the like, via geocasting. A signal is received atstep 402. The signal comprises a description of the geographic region ofintended reception of the signal. The signal can be received by anyappropriate communications device, such as a mobile communicationsdevice, for example. At step 404, the current location of thecommunication device is compared with the location of the geographicregion of intended reception. It is determined, at step 406 if thelocations match. That is, it is determined if the location of thereceiving communications device is the same as, within, or overlaps, thelocation of the geographic region of intended reception. If thelocations do not match, content of the message is not rendered at step410. If the locations match, appropriate content (e.g., alerting messagecontent) of the message is rendered, at step 408, via the receivingcommunications device. At step 412, it is determined if the message isto be retransmitted by the receiving communications device. If, at step412, it is determined that the message is not to be retransmitted, themessage is not retransmitted at step 414. If, at step 412, it isdetermined that the message is to be retransmitted, the message may beretransmitted at step 416, if appropriate, for example in accordancewith the above-described location-based approach.

In an embodiment, multiple geocast alerting regions may be created andmanaged by a single alerting system interface. Separate geocast alertingregions may be defined using any one of the above-discussed techniquesor a combination thereof. A geocast alerting region can be defined incommunications among members of an ad hoc geocast network within thegeocast alerting region. For example, information describing a geocastalerting region (e.g., location, size, shape, coordinates, range ofcoordinates, etc.) can be contained in packets communicated among themembers of the ad hoc network. The information could vary from packet topacket, vary as a function of time (e.g., the boundaries of the geocastalerting region may be redefined as the status of an emergent situationchanges with time), and/or predetermined and fixed prior tocommunications between members of the ad hoc network.

Geocast alerting regions may be defined manually, for example by a userinteracting with an alerting system interface. Alternatively, definitionof geocast alerting regions may be automated, for example with the useof mapping software. Geocast alerting regions may also be defined usinga combination of automated and manual processes. One or more sets ofdefault geocast alerting regions may be maintained by the alertingsystem. Each default set of geocast regions may be associated with aparticular type of emergent situation, for example fire, earthquake,shooting, hostage situation, severe weather, bomb threat, chemicalattack, and the like. The alerting system may be configured toautomatically distribute alerting messages to corresponding geocastregions when a default (i.e., predefined) emergent situation occurs, orthe system may be triggered manually through user interaction. Acombination of manual and automatic triggers may also be used. Thecontent of alerting messages transmitted during a default alertingprocess may be predetermined in accordance with the default geocastregions and/or the type of emergent situation, or may be determined inreal-time as alerting messages are transmitted.

Geocast regions may be redefined or otherwise modified when appropriate.Geocast region modifications can be entered manually by a user, can beauto-generated by the alerting system through a set of predefinedcriteria, or may be entered using a combination of techniques.Pre-defined geocast alerting regions, for example default alertingregions, can be redefined or otherwise modified when the alerting systemis not activated, or may be modified dynamically in real-time while thealerting system is activated. For example, geocast regions may bemodified based on trends or developments in an emergent situation, thesurrounding geographic area, and the like. The content of alertingmessages transmitted to a particular geocast alerting region may bedetermined coincidentally with modification of that geocast region.Geocast alerting regions may also be configured with dynamic behavior atthe time they are defined. In an embodiment, for example, a dynamicgeocast alerting region may be defined to comprise an initial geographicregion for a given interval of time. The geocast region may be definedsuch that the alerting region dynamically changes after the initialinterval of time expires. Dynamic changes might include translation ofthe geocast alerting region to a subsequent geographic location, varyingits size and/or shape, and the like. The dynamic changes may be:implemented according to a predetermined scheme; determined andimplemented by the alerting system in real-time according to newinformation and/or feedback into the alerting system, or the like; or acombination thereof

FIG. 5 depicts an example of a geocast alerting system, in particular analerting system for alerting mobile communication devices on a collegeor university campus. The example campus 500 comprises a series ofbuildings and roads. It is to be understood that the campus layoutdepicted, including the type, number, and placement of buildings, roads,and other features is merely exemplary and not to be construed aslimiting structure or function, and that the systems and methodsdisclosed herein may be applied to any physical arrangements ofbuildings, roads, infrastructure, and the like. Additionally, it is tobe understood that the depiction of a campus is exemplary and notintended to be limiting. Other environments suitable for deployment ofgeocast alerting include a metropolitan area disaster site, abattlefield, a campground, etc.

Separate geocast alerting regions are defined for discrete areas ofcampus 500. It is to be understood that the geocast alerting regionsdepicted in FIG. 5, including the number, size, shape, and geographiclocation of the alerting regions is merely exemplary and not to beconstrued as limiting structure or function. A first geocast alertingregion 502 is defined for a dormitory facility 504. Greater granularityin the definition of alerting regions for the dormitory facility 504 ispossible, for example separate alerting regions could be defined foreach floor of the dormitory. But, for the sake of simplicity, a singlegeocast alerting region 502 serves to distribute alerting messages amongall mobile communications devices within the building. A second alertingregion 506 is defined for a complex of interconnected classroombuildings 508. Again, multiple alerting regions or alerting sub-regionscould be defined within this complex, for example separate alertingregions for each floor, for each wing of classrooms, or even on aclassroom by classroom basis if desired, but a single alerting region isdepicted for the sake of simplicity. Two separate geocast alertingregions 510 and 512 are defined for the student union building 514. Thestudent union building 514 comprises two floors, with alerting regions510 and 512 defined for the first and second floors respectively. Asingle alerting region 516 has been defined for the campus sportsstadium 518, although multiple alerting regions or alerting sub-regionsare possible. Although FIG. 5 depicts independent geocast alertingregions, it would also be possible to define a “master” geocast alertingregion encompassing the entire geographic area of the campus. A mastergeocast region would be advantageous for simplified distribution ofalert messages that pertain equally to all individuals located oncampus, for example an alert message pertaining to a weather event.Individual geocast alerting sub regions, covering distinct geographicareas of the campus, for example the alerting regions 502, 506, 510,512, and 516, may be defined (i.e., carved out) within the masteralerting region. The alerting system may be configured to send alertingmessages to the master region, one or more of the sub regions, or anycombination thereof.

The creation of geocast alerting regions is not limited to physicalstructures such as buildings. Campus alerting regions have also beendefined for roads traversing the campus, in particular alerting region520 for the road running east to west along the north side of thestadium 518 and alerting region 522 for the road running north to southalong the west side of the stadium 518. It should be noted that thecreation of geocast alerting regions is not limited to buildings, roads,and the like. The locations, geometries, etc. of the geocast alertingregions depicted in FIG. 5 are merely exemplary and not to be construedas limiting structure or function.

In an example of an emergent situation for which the geocast campusalerting system may be used, a terrorist attack on the first floor ofthe student union building 514 has resulted in a hostage situation. Thepolice 524 receive notice of the emergent situation (not shown) andactivate the geocast campus alerting system in order to transmitalerting messages. The geocast alerting system may be secured to preventtransmission of fraudulent and/or unauthorized geocast alertingmessages. In an embodiment, control over the creation and/ortransmission of alerting messages is limited to authorized individuals,for example police, emergency personnel, etc. through the use ofpublic-key cryptography. For example, police and/or other individualsauthorized to transmit geocast alerting messages may be assigned and/orgenerate private/public key pairs in order to digitally sign alertingmessages. The public keys corresponding to the private keys may befreely distributed to communications devices configured to participatein geocast messaging. Alerting messages can be digitally signed and/orencrypted using an authorized sender's private key. An alerting messagesecured in such a way may only be rendered by a receiving device if thedigital signature can be verified. An alerting message signed with theprivate key of an authorized sender may be verified at a receivingcommunications device by applying the sender's corresponding public keyto decrypt the alerting message, allowing the alerting message contentto be rendered on the receiving communications device.

Once the alerting system has been activated, target geocast regionsand/or sub regions (i.e., those alerting regions and/or sub regions thatshould receive geocast alerting messages) may be identified. The processof identifying target geocast regions may begin by determining ageographic region that may potentially be affected by the emergentsituation (not shown). The size and scope of such a region may depend onmultiple factors, for example the type of the emergent situation, theseverity of the emergent situation, the time of day, the number ofmobile communication devices and/or people located proximally to theemergent situation, real-time traffic conditions, and the like. Thepotentially effected geographic region may be determined automaticallyby alerting system software, manually by a user of the alerting system,or by any combination thereof. In an alternate embodiment, multiplepotentially effected geographic regions may be determined separately orconcurrently.

Once a potentially effected geographic region has been determined, itmay be compared against predefined geocast alerting regions. Thecomparison may include determining whether the potentially effectedgeographic region is the same as, a part of, overlaps with, or is remotefrom each of the predefined geocast alerting regions. In an embodiment,if no predefined geocast alerting regions exist, a target geocastalerting region may be defined based on the potentially effectedgeographic region. Target geocast regions may be identified based on theresults of the comparison. The above-described process of identifyingtarget geocast regions and/or sub regions may be carried outautomatically by the alerting system, for example in accordance withdefault alerting scenarios and/or rules. For example, in the event of asevere weather event, such as an approaching ice storm that will affecta geographic region that includes the entirety of the campus, allgeocast alerting regions on campus may be identified as target geocastregions via a default alerting scenario. Alternatively, target geocastregions and/or sub regions that should receive alerting messages may beidentified and selected manually by a user of the alerting system, forexample through the use of an alerting system user interface. Forexample, in the terrorist attack and hostage situation of FIG. 5, thepotential geographic region likely to be affected by the hostagesituation may be defined as the student union and its immediatesurroundings. The potential effect of the hostage situation is likely tobe greatest for individuals located in the student union itself, and toa lesser degree for those located in other more remote geographic areasof the campus. As a result, geocast alerting regions 502, 506, 512, 520,and 522 may be manually identified as target geocast regions, for thereasons provided elsewhere herein.

Once target geocast regions and/or sub regions have been identified,customized alerting messages 526 containing appropriate informationand/or instructions can be transmitted to each of the target geocastalerting regions. The alerting messages are formatted in accordance witha scalable wireless geocast protocol that includes the location (e.g.,coordinates) of the sending, or transmitting, communications device anda description of the location (e.g., coordinates) of the target geocastalerting region. A receiving communications device, upon receiving analerting message 526, will compare the location of the target geocastalerting region, as provided in the alerting message 526, with itscurrent location. If the locations match, that is, if the location ofthe receiving communications device is the same as, within, or overlaps,the location of the target geocast alerting region, the alerting messageis further processed and content of the alerting message may be renderedon the receiving communications device. If the locations do not match,content of the alerting message is not rendered, and the alertingmessage may or may not be retransmitted by the receiving communicationsdevice.

Alerting messages may be transmitted from the campus alerting system viaa number of methods. In an embodiment, alerting message may betransmitted using the above-described techniques of tiered geocastingand forwarding zones, thereby avoiding the use of traditional wirelessnetwork elements and/or infrastructure. In another embodiment, alertingmessages may be transmitted from the campus alerting system via acombination of geocasting and traditional wireline and/or wirelessnetwork infrastructure. For example, alerting messages may be initiallytransmitted to one or more base station controllers located proximallyto the individual geocast alerting regions on campus (not shown). Thealerting messages may be retransmitted wirelessly from the base stationcontrollers and received by one or more mobile communications devices ineach alerting region that are configured to participate in geocastmessaging. The receiving communications devices may then retransmit thealerting messages within the ad hoc networks of their correspondinggeocast alerting regions.

Alerting messages can be customized for individual geocast alertingregions. One way that alerting messages may be customized is throughvarying the content of the altering messages. For example, the contentof alerting messages transmitted to alerting regions 502 and 506 mayinclude simple text to inform individuals at the corresponding locationsthat an emergency is taking place at the student union and to provideinstructions that individuals should stay in their current locations,return to their rooms, or the like. An alerting message with differentcontent may be transmitted to alerting region 512, the second floor ofthe student union. This alerting message might be more specific, and mayinclude text informing individuals that a terrorist attack has occurred,that a hostage situation is taking place on the first floor, that theterrorists/hostage takers are armed and dangerous, and instructingeveryone remaining on the second floor of the student union to move tothe northwest corner of the building for evacuation by emergencypersonnel. The text content may also be supplemented with additionalcontent, for example a map of the second floor of the student union fordisplay on the communications devices, directions to the evacuationsite, pictures of the terrorists, audible instructions, and the like.

Alerting messages may also contain multiple portions of content. One ormore portions of the content may be tailored based upon, for example, acontext condition associated with the target geocast alerting region. Acontext condition may relate to how a communications device is situatedwithin a geocast alerting region. Multiple context conditions may bespecified for a single geocast alerting region. Content provided basedupon the context condition may only be relevant for communicationsdevices meeting the context condition. For example, a portion ofalerting message content may be contextually linked to the conditionthat a communications device be moving in a particular direction, ormoving at a particular speed, etc. It is to be understood that thesemovement related conditions are merely exemplary and not to be construedas limiting structure or function. A portion of an alerting messagetailored based upon a context condition will be rendered only bycommunications devices to which the context condition applies. Tailoringa portion of alerting message content based upon a context condition mayallow for providing context specific information to communicationsdevices located within the target geocast region. Alerting messagescontaining portions of content tailored based upon a context conditionmay also contain portions of common content that apply universally toall communications devices located within a geocast alerting region, andshould thus be rendered by all communications devices within thatgeocast alerting region.

Alerting messages may also contain content portions tailored for varyingtypes of receiving devices. In an embodiment, the tailored portions mayall relate to the same alerting situation, but each portion may havedevice specific content associated with it. For example, an alertingmessage advising of the example terrorist attack may contain a firstcontent portion containing an image and/or text specifically formattedfor rendering on mobile communications devices with small and/or limiteddisplay screen resolutions. A second content portion may be formattedwith larger, more elaborate images suitable for display on mobilecommunications devices with larger display screen resolutions. Theindividual portions of content may be tagged such that a particularreceiving communications device will attempt to render only a portion ofcontent appropriate for display on that receiving device.

Returning to FIG. 5, an alerting message with a portion of commoncontent and portions of content tailored based upon context conditionsare transmitted to geocast alerting regions 520 and 522. For example,the context conditions may apply to a direction and/or speed of movementof motor vehicles 528 and 530. The portion of common content in thealerting messages received at geocast alerting regions 520 and 522 maybe relevant to all members of the respective geocast alerting regions,for example information that an emergency is taking place at the studentunion. The portions of content tailored based upon the direction and/orspeed of movement of the motor vehicles may provide, for instance,directions or instructions to motorists so that they avoid the area ofthe student union altogether. In another example, virtual detours may becreated directing motorists to circumvent the student union. Becauseappropriate directions and/or instructions may vary depending on thedirection of travel and speed of each particular motor vehicle, thealerting message may comprise multiple portions of content tailoredbased upon the context conditions. A communications device belonging toan ad hoc network in a geocast region and located in a moving motorvehicle may first determine whether the communications device is moving,and if so in what direction and at what speed.

Once this determination is made, the communications device may parse theportions of content tailored based on the context conditions, in orderto select and render an appropriate content portion. For example, motorvehicle 530, traveling east in geocast alerting region 520, may receivea geocast alerting message with a portion of common content and one ormore portions of content tailored according to the direction and/orspeed of movement of a communications devices in geocast alerting region520. The portion of common content may inform of an emergency at thestudent union. The mobile communications device associated with motorvehicle 530, upon receiving the alerting message and rendering thecommon content, may also determine that it is moving eastward at acertain speed, and may parse the alerting message for an appropriateportion of tailored content. For example, the alerting message maycontain a portion of tailored content for drivers heading east inalerting region 520. This portion of tailored content may provide, forexample, text, visual, and/or audio instructions that motorists shouldcontinue to drive straight, avoiding the student union. Additionally,the portion of tailored content may include information about streetclosures in the area, or other information related to the emergency.

A geocast alerting message is typically not rendered by a receivingmobile communications device if that device is not located in thegeographic location corresponding to the target geocast alerting region.For example, motor vehicle 532 traveling south near the student union,and a group of students 534 walking toward the student union are notcurrently located within one of the example campus geocast alertingregions, and therefore mobile communications devices located with motorvehicle 532 and/or students 534 may retransmit, but will likely notrender, geocast alerting messages pertaining to the terrorist attack.However, as these individuals enter one of the target geocast alertingregions, their respective mobile communications devices will thereafterrender geocast alerting messages transmitted to or retransmitted withinthe respective geocast alerting regions.

It is also possible with the geocast campus alerting system to excludeparticular geocast alerting regions from receiving alerting messages.For example, it may not be desirable to transmit alerting messages togeocast alerting region 510, the first floor of the student unionbuilding. Transmitting alerting messages to geocast region 510 presentsa risk that a terrorist/hostage taker with a mobile communicationsdevice may intercept an alerting message, which might in turn endangerindividuals attempting to escape from the second floor. Additionally, itmay not be desirable to transmit alerting messages to geocast region 516if a game is currently being played at the campus stadium 518.Distributing an alerting message regarding a campus emergency at acrowded stadium may cause unnecessary panic if the emergency is takingplace in an area of the campus remote from the stadium, presenting noimminent danger to spectators at the stadium. Accordingly, geocastalerting regions 510 and 516 are omitted from receiving alertingmessages pertaining to the terrorist attack/hostage situation.

Alerting messages may be customized for each individual geocast alertingregion. The content of the alerting messages may be determined manually,for example via an alerting system user interface, may be determinedautomatically by alerting system software, or may be determined using acombination of manual and auto-generated determinations. In anembodiment, geocast alerting software may determine the content ofalerting messages using a number of factors pertaining to a particulargeocast alerting region, for example the type of the emergent situation,the severity of the emergent situation, the distance of the geocastalerting region from the geographical location of the emergentsituation, the time of day, the number of mobile communication devicesand/or people located within the geocast alerting region, real-timetraffic conditions, and the like. The content of alerting messages mayalso be determined and provided by a user of a geocast alerting systeminterface. When transmitted alerting messages are received at one ormore mobile communications devices within the geocast alerting region,the alerting message may be retransmitted and distributed by and amongmobile communications devices of the corresponding ad hoc geocastnetwork.

Variable types of content may be contained within a geocast alertingmessage. In one embodiment, the alerting message may contain plain text.In another embodiment, a map may be provided as a standalone alertingmessage, or may be provided as a supplement to alerting message text. Analerting message map may be depicted on one or more display screens ofthe receiving mobile communications device. Maps included within orserving as alerting messages may be used to inform an individual withinthe geocast alerting region of important information pertaining to theemergent situation and/or information about the individual'ssurroundings. For example, an alerting message map may contain arepresentation of the current location of the receiving mobilecommunications device. The current location of the receiving mobilecommunications device may be depicted in respect to the location of theemergent situation. Additionally, the map may display the coordinates ofa safe location that the individual may retreat to. The mobilecommunications device may overlay directions to the safe locationvisually on the map display, may provide text or voice directions toaccompany the displayed map, or may use a combination of thesetechniques to guide the user to the safe location. The map and/ordirections may be updated dynamically as the emergent situation changeswith time. Alerting messages may also contain other forms of content ormedia, for example audio, video, pictures, graphics, images, multimedia,and the like. Content might also include links, for example hyperlinksor other electronic pointers directing a communications device to otherfiles or media stored locally or remotely from the receivingcommunications device, online information, online downloads, a serverproviding real-time information relating to the emergent situation, andthe like. A receiving communications device may render selected contentportions of a geocast alerting message based upon, for example, physicallimitations of the receiving communications device, preferences (e.g.,settings in a user profile), and the like.

Alerting messages comprising updated alerting information about theemergent situation may be transmitted to geocast alerting regions as theemergent situation changes with time. For example, when the terroristattack/hostage situation is resolved, updating alerting messages can betransmitted to all affected geocast alerting regions providinginformation that the threat no longer exists and that it is safe toresume normal activities. Updating alerting messages may be transmittedat prescribed intervals, or may be manually triggered by a user of thegeocast alerting system. The content of the updating alerting messagesmay be automatically determined, may be determined manually by a user ofthe geocast alerting system, or may be determined using a combination ofautomatic and manual determinations.

A specialized type of geocast message, namely a geographic query(“geoquery”) message, enables additional functionality in geocastalerting. A geoquery message functions to query all mobilecommunications devices within a specific geocast region that areconfigured to communicate via geocast messaging. A unique feature ofgeoquery messages is that they may specify whether a geoquery responsemessage from a receiving mobile communications device is mandatory orvoluntary. A geoquery packet may contain a number of portions, such asdestination and sending address portions, and a query content portion. Adestination address portion typically defines a geocast region withinwhich the geoquery message should be propagated. The geocast region fora geoquery message may be defined using the above-discussed techniquesfor defining geocast regions. A sending address portion may provide anindication of a location of the mobile communications device that firsttransmitted the geoquery message (i.e., the device from which themessage originated). The sending address portion may also act as areturn destination address for geoquery response message packetstransmitted by receiving communications devices in response to thegeoquery message. The query content portion contains the substance ofthe query and may also contain an indicator of whether a geoqueryresponse message by a receiving communications device is mandatory orvoluntary. In an embodiment, if a geoquery response message ismandatory, the receiving communications device may transmit a geoqueryresponse message automatically, regardless of interaction from a user ofthe receiving communications device. Alternatively, a user of thereceiving communications device may be presented with an opportunity tocompose content for inclusion in the mandatory geoquery response messagebefore it is transmitted.

In an embodiment, an example use of geoquery messaging is to locatesurvivors at the scene of an emergent situation. For example, in theevent of a partial building collapse, an emergency responder maytransmit a first type of geoquery alerting message with a mandatoryresponse indicator and containing: a destination address portiondefining a geocast region encompassing the immediate vicinity of thecollapsed building; a sending address portion corresponding to thegeographic location of the emergency responder; and a query contentportion. The query content portion may comprise a question to beanswered by users of receiving communications devices, for example, “Areyou hurt?”, “Are you able to exit the building?”, or the like. Eachmobile communications device located within the geocast region andconfigured for geocast messaging will transmit a corresponding geoqueryresponse message. The geoquery response message may contain adestination address portion corresponding to the emergency responder'slocation, a sending address portion identifying the geographic locationof the receiving mobile communications device, and a query responsecontent portion. The query response content portion may contain a userresponse to the query content portion. If no user interaction isdetected by the receiving communications device within a specificinterval of time, the receiving communications device may transmit ageoquery response message automatically, perhaps containing queryresponse content indicating that no user interaction is available. Inanother embodiment, if the receiving mobile communications device iscapable of detecting biometric feedback from the user in possession ofthe receiving mobile communications device, information pertaining tothat feedback may be encapsulated within the query response content.When the geoquery response message is received at the mobilecommunications device of the emergency responder, an indication of thegeographic location of the receiving device may be rendered on a displayof the emergency responder's mobile communications device. Theindication may comprise, for example, an icon overlaid on a graphicalmap of the geoquery destination geocast region. The emergency respondermay use such an indication to determine and/or reach the location of thereceiving communications device within the partially collapsed building.

In another embodiment, the emergency responder may transmit a secondtype of geoquery message. Like the first type of geoquery message, thesecond type of geoquery message may contain similar portions and requirea mandatory geoquery response from a receiving communications device.However, the mandatory geoquery response to this second type of geoquerymessage may comprise executing a behavior routine on the receivingcommunications device. In an embodiment, a preprogrammed behaviorroutine may be stored within a memory on the receiving communicationsdevice. The query content portion of the geoquery message may contain acommand or other form of instructions that, when the query contentportion is rendered by the receiving communications device, causes thereceiving communications device to invoke the behavior routine. Inanother embodiment, the query portion may contain a list of scriptcommands, or any other appropriate form of programming, that areexecuted on the receiving communications device when the query contentportion is rendered by the receiving communications device. The scriptcommands, when executed, may invoke the behavior routine on thereceiving communications device.

Behavior routines may be simple or complex, and may invoke variousfeatures and/or functions of the receiving communications device, asappropriate. For example, a behavior routine may cause a receivingcommunications device to awaken from a sleep mode, flash a light sourceon the device such as a display screen, emit an audible tone, vibrate,and/or send a message, and return to the sleep mode. The behaviorroutine may be invoked repeatedly in a pattern at specified timeintervals. It is to be understood that the behavior routine describedherein is merely an example, and that the scope of the instantdisclosure should not be limited thereto.

This second type of geoquery message may be advantageous in locating theuser of a receiving communications device who is incapacitated orotherwise unable to respond to an initial geoquery message, for examplein a scenario when an emergency responder reaches the geographiclocation indicated in a geoquery response message to the first type ofgeoquery message, but still fails to locate the receiving communicationsdevice or its user (e.g., when the device and/or user are buriedunderneath rubble). The first responder may send a geoquery message ofthe same type to invoke an audible beeping behavior routine on theburied user's communications device. When the mobile communicationsdevice renders the geoquery message, the beeping routine will be invokedand the first responder my then follow the audible tone emitted by thereceiving communications device in order to better pinpoint its exactlocation. The audible tone emitted by the buried user's communicationsdevice may be configured to modulate as the distance shortens betweenthe emergency responder's communications device and the buried user'scommunications device. The audible tone may be modulated in a variety ofways, for instance by volume, by pitch, by repetition speed, and thelike. It is to be understood that the use of an audible tone is merelyan example of a locator function that may be activated on a receivingcommunications device, and the scope of the instant disclosure shouldnot be limited thereto.

In another embodiment, geoquery messages may be employed in a logisticalcontext. Geoquery messages may be used to obtain helpful situationalinformation for a geocast alerting region. Information such as thenumber of receiving mobile communications devices located in aparticular geocast region may be useful to emergency responders increating plans for how to handle logistical aspects of responding to anemergent situation. For example, referring again to FIG. 5, the numberof receiving mobile communications devices in alerting region 512,indicating a rough estimate of the number of individuals on the secondfloor of the student union, may be gathered via geoquery responsemessages. This information might allow emergency responders to deployappropriate measures of manpower and/or equipment to rescue theindividuals on the second floor of the student union building.Additional information may be gathered from geoquery response messages.For example, a geoquery response message might contain within the queryresponse content portion information associated with each receivingmobile communications device in the geocast region, such as the mobileidentification number (MIN) assigned to the device, the device'selectronic serial number (ESN), and the like. This information may allowpolice and/or emergency responders to discover the identity ofindividuals who are located within the geocast alerting region.

In an embodiment, receipt of a geocast alerting message may preemptother applications or functions executing on the mobile communicationsdevice. For example, a phone call taking place on a receiving mobilecommunications device may be temporarily interrupted so the user of themobile communications device may be informed of the arrival of thegeocast alerting message. After interruption of the executing function,the user may be provided with an option to render the content of thegeocast alerting information immediately, or at another time of theuser's choosing. Alternatively, the geocast alerting message may beautomatically rendered by the mobile communications device withoutquerying the user for permission to render the content, or the user maynot be allowed to execute other applications and/or functions on themobile communications device before acknowledging receipt of thealerting message.

FIG. 6 is a block diagram of an example communications device 600configured to communicate in an ad hoc network of communications devicesin accordance with a scalable wireless geocast protocol. In an exampleconfiguration, communications device 600 is a mobile wireless device.The communications device can comprise any appropriate device, examplesof which include a portable computing device, such as a laptop, apersonal digital assistant (“PDA”), a portable phone (e.g., a cell phoneor the like, a smart phone, a video phone), a portable email device, aportable gaming device, a TV, a DVD player, portable media player,(e.g., a portable music player, such as an MP3 player, a walkmans,etc.), a portable navigation device (e.g., GPS compatible device, A-GPScompatible device, etc.), or a combination thereof. The communicationsdevice 600 can include devices that are not typically thought of asportable, such as, for example, a public computing device, a navigationdevice installed in-vehicle, a set top box, or the like. Thecommunications device 600 can include non-conventional computingdevices, such as, for example, a kitchen appliance, a motor vehiclecontrol (e.g., steering wheel), etc., or the like.

The communications device 600 can include any appropriate device,mechanism, software, and/or hardware for communication in an ad hocnetwork of communications devices in accordance with a scalable wirelessgeocast protocol as described herein. In an example embodiment, theability to communicate in an ad hoc network of communications devices inaccordance with a scalable wireless geocast protocol is a feature of thecommunications device 600 that can be turned on and off. Thus, an ownerof the communications device 600 can opt-in or opt-out of thiscapability.

In an example configuration, the communications device 600 comprises aprocessing portion 602, a memory portion 604, an input/output portion606, and a user interface (UI) portion 608. It is emphasized that theblock diagram depiction of communications device 600 is exemplary andnot intended to imply a specific implementation and/or configuration.For example, in an example configuration, the communications device 600comprises a cellular phone and the processing portion 602 and/or thememory portion 604 are implemented, in part or in total, on a subscriberidentity module (SIM) of the communications device. In another exampleconfiguration, the communications device 600 comprises a laptopcomputer. The laptop computer can include a SIM, and various portions ofthe processing portion 602 and/or the memory portion 604 can beimplemented on the SIM, on the laptop other than the SIM, or anycombination thereof.

The processing portion 602, memory portion 604, and input/output portion606 are coupled together to allow communications therebetween. Invarious embodiments, the input/output portion 606 comprises a receiverof the communications device 600, a transmitter of the communicationsdevice, or a combination thereof. The input/output portion 606 iscapable of receiving and/or providing information pertaining tocommunication in an ad hoc network of communications devices inaccordance with a scalable wireless geocast protocol as described above.For example, the input/output portion 606 is capable of receiving and/orsending a message containing geographic information pertaining to ageocast alerting region, geocast alerting message content, and the like,as described herein. In an example embodiment, the input/output portionis capable of receiving and/or sending information to determine alocation of the communications device. In an example configuration, theinput\output portion 606 comprises a GPS receiver. In variousconfigurations, the input/output portion can receive and/or provideinformation via any appropriate means, such as, for example, opticalmeans (e.g., infrared), electromagnetic means (e.g., RF, Wi-Fi,Bluetooth®, ZigBee™, etc.), acoustic means (e.g., speaker, microphone,ultrasonic receiver, ultrasonic transmitter), or a combination thereof.

The processing portion 602 is capable of performing functions pertainingto communicating in an ad hoc network of communications devices inaccordance with a scalable wireless geocast protocol as described above.For example, the processing portion 602 is capable of determiningmessage content, such as location information, alerting content, whetherthe communications device has previously received the same message atleast a predetermined number of times, whether a sending communicationsdevice is closer than a minimum distance away, whether thecommunications device is closer to the center of a geocast region thanany sending communications device from which a message was received, orthe like, as described above. Message content can comprise text, maps,audio, video, pictures, graphics, images, multimedia, links todownloadable information, or any combination thereof.

In a basic configuration, the communications device 600 can include atleast one memory portion 604. The memory portion can store anyinformation utilized in conjunction with communicating in an ad hocnetwork of communications devices in accordance with a scalable wirelessgeocast protocol as described above. For example, the memory portion 604is capable of storing information pertaining to a location of acommunications device, a location of a geocast region, a content type,the number of times a message has previously been received by thecommunications device, whether a sending communications device is closerthan a minimum distance, whether the communications device is closer tothe center of a geocast region than any sending communications devicefrom which a message was received, or a combination thereof, asdescribed above. Depending upon the exact configuration and type ofprocessor, the memory portion 604 can be volatile (such as some types ofRAM), non-volatile (such as ROM, flash memory, etc.), or a combinationthereof. The mobile communications device 600 can include additionalstorage (e.g., removable storage and/or non-removable storage)including, but not limited to, tape, flash memory, smart cards, CD-ROM,digital versatile disks (DVD) or other optical storage, magneticcassettes, magnetic tape, magnetic disk storage or other magneticstorage devices, universal serial bus (USB) compatible memory, or anyother medium which can be used to store information and which can beaccessed by the mobile communications device.

The communications device 600 also can contain a user interface (UI)portion 608 allowing a user to communicate with the communicationsdevice. The UI portion is capable of rendering any information utilizedin conjunction with communicating in an ad hoc network of communicationsdevices in accordance with a scalable wireless geocast protocol asdescribed above. For example, the UI portion can render geocast alertingmessage content or the like, as described above. The UI portion canprovide the ability to control the communications device, via, forexample, buttons, soft keys, voice actuated controls, a touch screen,movement of the communications device, visual cues (e.g., moving a handin front of a camera integrated in the communications device (notshown)), or the like. The UI portion can provide visual information(e.g., via a display), audio information (e.g., via speaker),mechanically (e.g., via a vibrating mechanism), or a combinationthereof. In various configurations, the UI portion 608 can comprise adisplay, a touch screen, a keyboard, an accelerometer, a motiondetector, a speaker, a microphone, a camera, a tilt sensor, or anycombination thereof. The UI portion 608 can comprise means for inputtingbiometric information, such as, for example, fingerprint information,retinal information, voice information, and/or facial characteristicinformation.

Although not necessary to implement communications in an ad hoc networkof communications devices in accordance with a scalable wireless geocastprotocol, the communications device 600 can be part of and/or incommunications with various wireless communications networks and/ornetwork components. Some of which are described below.

FIG. 7 depicts an example packet-based mobile cellular networkenvironment, such as a GPRS network, in which communications in an adhoc network of communications devices in accordance with a scalablewireless geocast protocol can be implemented. In the examplepacket-based mobile cellular network environment shown in FIG. 7, thereare a plurality of Base Station Subsystems (“BSS”) 700 (only one isshown), each of which comprises a Base Station Controller (“BSC”) 702serving a plurality of Base Transceiver Stations (“BTS”) such as BTSs704, 706, and 708. BTSs 704, 706, 708, etc. are the access points whereusers of packet-based mobile devices become connected to the wirelessnetwork. In exemplary fashion, the packet traffic originating from userdevices is transported via an over-the-air interface to a BTS 708, andfrom the BTS 708 to the BSC 702. Base station subsystems, such as BSS700, are a part of internal frame relay network 710 that can includeService GPRS Support Nodes (“SGSN”) such as SGSN 712 and 714. Each SGSNis connected to an internal packet network 720 through which a SGSN 712,714, etc. can route data packets to and from a plurality of gateway GPRSsupport nodes (GGSN) 722, 724, 726, etc. As illustrated, SGSN 714 andGGSNs 722, 724, and 726 are part of internal packet network 720. GatewayGPRS serving nodes 722, 724 and 726 mainly provide an interface toexternal Internet Protocol (“IP”) networks such as Public Land MobileNetwork (“PLMN”) 750, corporate intranets 740, or Fixed-End System(“FES”) or the public Internet 730. As illustrated, subscriber corporatenetwork 740 may be connected to GGSN 724 via firewall 732; and PLMN 750is connected to GGSN 724 via boarder gateway router 734. The RemoteAuthentication Dial-In User Service (“RADIUS”) server 742 may be usedfor caller authentication when a user of a mobile cellular device callscorporate network 740.

Generally, there can be a several cell sizes in a GSM network, referredto as macro, micro, pico, femto and umbrella cells. The coverage area ofeach cell is different in different environments. Macro cells can beregarded as cells in which the base station antenna is installed in amast or a building above average roof top level. Micro cells are cellswhose antenna height is under average roof top level. Micro-cells aretypically used in urban areas. Pico cells are small cells having adiameter of a few dozen meters. Pico cells are used mainly indoors.Femto cells have the same size as pico cells, but a smaller transportcapacity. Femto cells are used indoors, in residential or small businessenvironments. On the other hand, umbrella cells are used to covershadowed regions of smaller cells and fill in gaps in coverage betweenthose cells.

FIG. 8 illustrates an architecture of a typical GPRS network in whichcommunications in an ad hoc network of communications devices inaccordance with a scalable wireless geocast protocol can be implemented.The architecture depicted in FIG. 8 is segmented into four groups: users850, radio access network 860, core network 870, and interconnectnetwork 880. Users 850 comprise a plurality of end users. Note: device812 is referred to as a mobile subscriber in the description of thenetwork shown in FIG. 8. In an example embodiment, the device depictedas mobile subscriber 812 comprises a communications device (e.g.,communications device 600). Radio access network 860 comprises aplurality of base station subsystems such as BSSs 862, which includeBTSs 864 and BSCs 866. Core network 870 comprises a host of variousnetwork elements. As illustrated in FIG. 8, core network 870 maycomprise Mobile Switching Center (“MSC”) 871, Service Control Point(“SCP”) 872, gateway MSC 873, SGSN 876, Home Location Register (“HLR”)874, Authentication Center (“AuC”) 875, Domain Name Server (“DNS”) 877,and GGSN 878. Interconnect network 880 also comprises a host of variousnetworks and other network elements. As illustrated in FIG. 8,interconnect network 880 comprises Public Switched Telephone Network(“PSTN”) 882, Fixed-End System (“FES”) or Internet 884, firewall 888,and Corporate Network 889.

A mobile switching center can be connected to a large number of basestation controllers. At MSC 871, for instance, depending on the type oftraffic, the traffic may be separated in that voice may be sent toPublic Switched Telephone Network (“PSTN”) 882 through Gateway MSC(“GMSC”) 873, and/or data may be sent to SGSN 876, which then sends thedata traffic to GGSN 878 for further forwarding.

When MSC 871 receives call traffic, for example from BSC 866, it sends aquery to a database hosted by SCP 872. The SCP 872 processes the requestand issues a response to MSC 871 so that it may continue call processingas appropriate.

The HLR 874 is a centralized database for users to register to the GPRSnetwork. HLR 874 stores static information about the subscribers such asthe International Mobile Subscriber Identity (“IMSI”), subscribedservices, and a key for authenticating the subscriber. HLR 874 alsostores dynamic subscriber information such as the current location ofthe mobile subscriber. Associated with HLR 874 is AuC 875. AuC 875 is adatabase that contains the algorithms for authenticating subscribers andincludes the associated keys for encryption to safeguard the user inputfor authentication.

In the following, depending on context, the term “mobile subscriber”sometimes refers to the end user and sometimes to the actual portabledevice, such as a mobile device, used by an end user of the mobilecellular service. When a mobile subscriber turns on his or her mobiledevice, the mobile device goes through an attach process by which themobile device attaches to an SGSN of the GPRS network. In FIG. 8, whenthe mobile subscriber 812 initiates the attach process by turning on thenetwork capabilities of the mobile device, an attach request is sent bymobile subscriber 812 to SGSN 876. The SGSN 876 queries another SGSN, towhich mobile subscriber 812 was attached before, for the identity ofmobile subscriber 812. Upon receiving the identity of mobile subscriber812 from the other SGSN, SGSN 876 requests more information from mobilesubscriber 812. This information is used to authenticate mobilesubscriber 812 to SGSN 876 by HLR 874. Once verified, SGSN 876 sends alocation update to HLR 874 indicating the change of location to a newSGSN, in this case SGSN 876. HLR 874 notifies the old SGSN, to whichmobile subscriber 812 was attached before, to cancel the locationprocess for mobile subscriber 812. HLR 874 then notifies SGSN 876 thatthe location update has been performed. At this time, SGSN 876 sends anAttach Accept message to mobile subscriber 812, which in turn sends anAttach Complete message to SGSN 876.

After attaching itself with the network, mobile subscriber 812 then goesthrough the authentication process. In the authentication process, SGSN876 sends the authentication information to HLR 874, which sendsinformation back to SGSN 876 based on the user profile that was part ofthe user's initial setup. The SGSN 876 then sends a request forauthentication and ciphering to mobile subscriber 812. The mobilesubscriber 812 uses an algorithm to send the user identification (ID)and password to SGSN 876. The SGSN 876 uses the same algorithm andcompares the result. If a match occurs, SGSN 876 authenticates mobilesubscriber 812.

Next, the mobile subscriber 812 establishes a user session with thedestination network, corporate network 889, by going through a PacketData Protocol (“PDP”) activation process. Briefly, in the process,mobile subscriber 812 requests access to the Access Point Name (“APN”),for example, UPS.com, and SGSN 876 receives the activation request frommobile subscriber 812. SGSN 876 then initiates a Domain Name Service(“DNS”) query to learn which GGSN node has access to the UPS.com APN.The DNS query is sent to the DNS server within the core network 870,such as DNS 877, which is provisioned to map to one or more GGSN nodesin the core network 870. Based on the APN, the mapped GGSN 878 canaccess the requested corporate network 889. The SGSN 876 then sends toGGSN 878 a Create Packet Data Protocol (“PDP”) Context Request messagethat contains necessary information. The GGSN 878 sends a Create PDPContext Response message to SGSN 876, which then sends an Activate PDPContext Accept message to mobile subscriber 812.

Once activated, data packets of the call made by mobile subscriber 812can then go through radio access network 860, core network 870, andinterconnect network 880, in a particular fixed-end system or Internet884 and firewall 888, to reach corporate network 889.

FIG. 9 illustrates an example GSM/GPRS/IP multimedia networkarchitecture within which communications in an ad hoc network ofcommunications devices in accordance with a scalable wireless geocastprotocol can be implemented. As illustrated, the architecture of FIG. 9includes a GSM core network 901, a GPRS network 930 and an IP multimedianetwork 938. The GSM core network 901 includes a Mobile Station (MS)902, at least one Base Transceiver Station (BTS) 904 and a Base StationController (BSC) 906. The MS 902 is physical equipment or MobileEquipment (ME), such as a mobile phone or a laptop computer that is usedby mobile subscribers, with a Subscriber Identity Module (SIM) or aUniversal Integrated Circuit Card (UICC). The SIM or UICC includes anInternational Mobile Subscriber Identity (IMSI), which is a uniqueidentifier of a subscriber. The BTS 904 is physical equipment, such as aradio tower, that enables a radio interface to communicate with the MS.Each BTS may serve more than one MS. The BSC 906 manages radioresources, including the BTS. The BSC may be connected to several BTSs.The BSC and BTS components, in combination, are generally referred to asa base station subsystem (BSS) or radio access network (RAN) 903.

The GSM core network 901 also includes a Mobile Switching Center (MSC)908, a Gateway Mobile Switching Center (GMSC) 910, a Home LocationRegister (HLR) 912, Visitor Location Register (VLR) 914, anAuthentication Center (AuC) 916, and an Equipment Identity Register(EIR) 918. The MSC 908 performs a switching function for the network.The MSC also performs other functions, such as registration,authentication, location updating, handovers, and call routing. The GMSC910 provides a gateway between the GSM network and other networks, suchas an Integrated Services Digital Network (ISDN) or Public SwitchedTelephone Networks (PSTNs) 920. Thus, the GMSC 910 provides interworkingfunctionality with external networks.

The HLR 912 is a database that contains administrative informationregarding each subscriber registered in a corresponding GSM network. TheHLR 912 also contains the current location of each MS. The VLR 914 is adatabase that contains selected administrative information from the HLR912. The VLR contains information necessary for call control andprovision of subscribed services for each MS currently located in ageographical area controlled by the VLR. The HLR 912 and the VLR 914,together with the MSC 908, provide the call routing and roamingcapabilities of GSM. The AuC 916 provides the parameters needed forauthentication and encryption functions. Such parameters allowverification of a subscriber's identity. The EIR 918 storessecurity-sensitive information about the mobile equipment.

A Short Message Service Center (SMSC) 909 allows one-to-one ShortMessage Service (SMS) messages to be sent to/from the MS 902. A PushProxy Gateway (PPG) 911 is used to “push” (i.e., send without asynchronous request) content to the MS 902. The PPG 911 acts as a proxybetween wired and wireless networks to facilitate pushing of data to theMS 902. A Short Message Peer to Peer (SMPP) protocol router 913 isprovided to convert SMS-based SMPP messages to cell broadcast messages.SMPP is a protocol for exchanging SMS messages between SMS peer entitiessuch as short message service centers. The SMPP protocol is often usedto allow third parties, e.g., content suppliers such as newsorganizations, to submit bulk messages.

To gain access to GSM services, such as speech, data, and short messageservice (SMS), the MS first registers with the network to indicate itscurrent location by performing a location update and IMSI attachprocedure. The MS 902 sends a location update including its currentlocation information to the MSC/VLR, via the BTS 904 and the BSC 906.The location information is then sent to the MS's HLR. The HLR isupdated with the location information received from the MSC/VLR. Thelocation update also is performed when the MS moves to a new locationarea. Typically, the location update is periodically performed to updatethe database as location updating events occur.

The GPRS network 930 is logically implemented on the GSM core networkarchitecture by introducing two packet-switching network nodes, aserving GPRS support node (SGSN) 932, a cell broadcast and a GatewayGPRS support node (GGSN) 934. The SGSN 932 is at the same hierarchicallevel as the MSC 908 in the GSM network. The SGSN controls theconnection between the GPRS network and the MS 902. The SGSN also keepstrack of individual MS's locations and security functions and accesscontrols.

A Cell Broadcast Center (CBC) 935 communicates cell broadcast messagesthat are typically delivered to multiple users in a specified area. CellBroadcast is one-to-many geographically focused service. It enablesmessages to be communicated to multiple mobile phone customers who arelocated within a given part of its network coverage area at the time themessage is broadcast.

The GGSN 934 provides a gateway between the GPRS network and a publicpacket network (PDN) or other IP networks 936. That is, the GGSNprovides interworking functionality with external networks, and sets upa logical link to the MS through the SGSN. When packet-switched dataleaves the GPRS network, it is transferred to an external TCP-IP network936, such as an X.25 network or the Internet. In order to access GPRSservices, the MS first attaches itself to the GPRS network by performingan attach procedure. The MS then activates a packet data protocol (PDP)context, thus activating a packet communication session between the MS,the SGSN, and the GGSN.

In a GSM/GPRS network, GPRS services and GSM services can be used inparallel. The MS can operate in one of three classes: class A, class B,and class C. A class A MS can attach to the network for both GPRSservices and GSM services simultaneously. A class A MS also supportssimultaneous operation of GPRS services and GSM services. For example,class A mobiles can receive GSM voice/data/SMS calls and GPRS data callsat the same time.

A class B MS can attach to the network for both GPRS services and GSMservices simultaneously. However, a class B MS does not supportsimultaneous operation of the GPRS services and GSM services. That is, aclass B MS can only use one of the two services at a given time.

A class C MS can attach for only one of the GPRS services and GSMservices at a time. Simultaneous attachment and operation of GPRSservices and GSM services is not possible with a class C MS.

A GPRS network 930 can be designed to operate in three network operationmodes (NOM1, NOM2 and NOM3). A network operation mode of a GPRS networkis indicated by a parameter in system information messages transmittedwithin a cell. The system information messages dictates a MS where tolisten for paging messages and how to signal towards the network. Thenetwork operation mode represents the capabilities of the GPRS network.In a NOM1 network, a MS can receive pages from a circuit switched domain(voice call) when engaged in a data call. The MS can suspend the datacall or take both simultaneously, depending on the ability of the MS. Ina NOM2 network, a MS may not receive pages from a circuit switcheddomain when engaged in a data call, since the MS is receiving data andis not listening to a paging channel. In a NOM3 network, a MS canmonitor pages for a circuit switched network while receiving data andvise versa.

The IP multimedia network 938 was introduced with 3GPP Release 5, andincludes an IP multimedia subsystem (IMS) 940 to provide rich multimediaservices to end users. A representative set of the network entitieswithin the IMS 940 are a call/session control function (CSCF), a mediagateway control function (MGCF) 946, a media gateway (MGW) 948, and amaster subscriber database, called a home subscriber server (HSS) 950.The HSS 950 may be common to the GSM network 901, the GPRS network 930as well as the IP multimedia network 938.

The IP multimedia system 940 is built around the call/session controlfunction, of which there are three types: an interrogating CSCF (I-CSCF)943, a proxy CSCF (P-CSCF) 942, and a serving CSCF (S-CSCF) 944. TheP-CSCF 942 is the MS's first point of contact with the IMS 940. TheP-CSCF 942 forwards session initiation protocol (SIP) messages receivedfrom the MS to an SIP server in a home network (and vice versa) of theMS. The P-CSCF 942 may also modify an outgoing request according to aset of rules defined by the network operator (for example, addressanalysis and potential modification).

The I-CSCF 943, forms an entrance to a home network and hides the innertopology of the home network from other networks and providesflexibility for selecting an S-CSCF. The I-CSCF 943 may contact asubscriber location function (SLF) 945 to determine which HSS 950 to usefor the particular subscriber, if multiple HSSs 950 are present. TheS-CSCF 944 performs the session control services for the MS 902. Thisincludes routing originating sessions to external networks and routingterminating sessions to visited networks. The S-CSCF 944 also decideswhether an application server (AS) 952 is required to receiveinformation on an incoming SIP session request to ensure appropriateservice handling. This decision is based on information received fromthe HSS 950 (or other sources, such as an application server 952). TheAS 952 also communicates to a location server 956 (e.g., a GatewayMobile Location Center (GMLC)) that provides a position (e.g.,latitude/longitude coordinates) of the MS 902.

The HSS 950 contains a subscriber profile and keeps track of which corenetwork node is currently handling the subscriber. It also supportssubscriber authentication and authorization functions (AAA). In networkswith more than one HSS 950, a subscriber location function providesinformation on the HSS 950 that contains the profile of a givensubscriber.

The MGCF 946 provides interworking functionality between SIP sessioncontrol signaling from the IMS 940 and ISUP/BICC call control signalingfrom the external GSTN networks (not shown). It also controls the mediagateway (MGW) 948 that provides user-plane interworking functionality(e.g., converting between AMR- and PCM-coded voice). The MGW 948 alsocommunicates with other IP multimedia networks 954.

Push to Talk over Cellular (PoC) capable mobile phones register with thewireless network when the phones are in a predefined area (e.g., jobsite, etc.). When the mobile phones leave the area, they register withthe network in their new location as being outside the predefined area.This registration, however, does not indicate the actual physicallocation of the mobile phones outside the predefined area.

The various techniques for geocast alerting described herein can beimplemented in connection with hardware or software or, whereappropriate, with a combination of both. Thus, the methods andapparatuses for transmitting geocast alerting messages and otherwisecommunicating in an ad hoc network of communications devices inaccordance with a scalable wireless geocast protocol can be implemented,or certain aspects or portions thereof, can take the form of programcode (i.e., instructions) embodied in tangible storage media, such asfloppy diskettes, CD-ROMs, hard drives, or any other machine-readablestorage medium (computer-readable storage medium), wherein, when theprogram code is loaded into and executed by a machine, such as acomputer, the machine becomes an apparatus for geocast alerting. In thecase of program code execution on programmable computers, the computingdevice will generally include a processor, a storage medium readable bythe processor (including volatile and non-volatile memory and/or storageelements), at least one input device, and at least one output device.The program(s) can be implemented in assembly or machine language, ifdesired. The language can be a compiled or interpreted language, andcombined with hardware implementations.

The methods and apparatuses for communicating in an ad hoc network ofcommunications devices in accordance with a scalable wireless geocastprotocol also can be practiced via communications embodied in the formof program code that is transmitted over some transmission medium, suchas over electrical wiring or cabling, through fiber optics, or via anyother form of transmission, wherein, when the program code is receivedand loaded into and executed by a machine, such as an EPROM, a gatearray, a programmable logic device (PLD), a client computer, or thelike, the machine becomes an apparatus for geocast alerting. Whenimplemented on a general-purpose processor, the program code combineswith the processor to provide a unique apparatus that operates to invokethe functionality of communicating in an ad hoc network ofcommunications devices in accordance with a scalable wireless geocastprotocol. Additionally, any storage techniques used in connection withcommunicating in an ad hoc network of communications devices inaccordance with a scalable wireless geocast protocol can invariably be acombination of hardware and software.

While transmission and propagation of alerting messages viacommunications in an ad hoc network of communications devices inaccordance with a scalable wireless geocast protocol have been describedin connection with the various embodiments of the various figures, it isto be understood that other similar embodiments can be used ormodifications and additions can be made to the described embodiments fortransmission and propagation of alerting messages in an ad hoc networkof communications devices in accordance with a scalable wireless geocastprotocol without deviating therefrom. For example, one skilled in theart will recognize that communicating in an ad hoc network ofcommunications devices in accordance with a scalable wireless geocastprotocol as described in the present application may apply to anyenvironment, whether wired or wireless, and may be applied to any numberof such devices connected via a communications network and interactingacross the network. Therefore, transmission and propagation of alertingmessages in an ad hoc network of communications devices in accordancewith a scalable wireless geocast protocol should not be limited to anysingle embodiment, but rather should be construed in breadth and scopein accordance with the appended claims.

What is claimed:
 1. An apparatus comprising: a processor; and memorycoupled to the processor, the memory comprising executable instructionsthat when executed by the processor cause the processor to effectuateoperations comprising: identifying a target geographic region forreceipt of an alerting message pertaining to an emergent situation; andproviding the alerting message, the alerting message comprising anindication of the target geographic region and an indication of theemergent situation, wherein: the alerting message is renderable by arecipient device of the alerting message based on a determination by therecipient device that a location at which the alerting message isreceived is within the target geographic region; and the alertingmessage is retransmittable by the recipient device based on adetermination by the recipient device that the alerting message has beenreceived at least a predetermined number of times.
 2. The apparatus ofclaim 1, wherein: the alerting message is not renderable by therecipient device when a location at which the alerting message isreceived is not within the target geographic region.
 3. The apparatus ofclaim 1, wherein: the alerting message is not retransmittable by therecipient device when the alerting message has not been received atleast a predetermined number of times.
 4. The apparatus of claim 1, theoperations further comprising: identifying a plurality of targetgeographic regions for receipt of a respective plurality of alertingmessages pertaining to the emergent situation; determining respectivecontent for each of the plurality of alerting messages; and providingthe plurality of alerting messages, each of the plurality of alertingmessage comprising: an indication of a respective target geographicregion; and an indication of respective content.
 5. The apparatus ofclaim 1, wherein: the alerting message comprises a plurality of contentportions; each of the plurality of content portions comprises contenttailored to a respective target geographic region; tailored content isrenderable by a recipient of the alerting message when a location atwhich the alerting message is received is within a respective targetgeographic region for the tailored content; and tailored content is notrenderable by a recipient of the alerting message when a location atwhich the alerting message is received is not within a respective targetgeographic region for the tailored content.
 6. The apparatus of claim 1,wherein: the alerting message further comprises a behavior routine; andthe behavior routine is invokable by a recipient of the alerting messagewhen the alerting message is renderable by the recipient.
 7. Theapparatus of claim 1, wherein content of the alerting message isdetermined at a time when the indication of the emergent situation isreceived.
 8. The apparatus of claim 1, wherein: the alerting message isretransmittable by a recipient of the alerting message when the alertingmessage has been received at least a predetermined number of times andthe alerting message was not sent from a location closer than a minimumdistance from the location at which the alerting message was received;and the alerting message is not retransmittable by a recipient of thealerting message when the alerting message has not been received atleast a predetermined number of times or the alerting message was sentfrom a location closer than a minimum distance from the location atwhich the alerting message was received.
 9. An apparatus comprising: aprocessor; and memory coupled to the processor, the memory comprisingexecutable instructions that when executed by the processor cause theprocessor to effectuate operations comprising: identifying a targetgeographic region for receipt of an alerting message pertaining to anemergent situation; and providing the alerting message, the alertingmessage comprising an indication of the target geographic region and anindication of the emergent situation, wherein: the alerting message isrenderable by a recipient device of the alerting message based onrelative movement of the recipient device to the target geographicregion; and the alerting message is retransmittable by the recipientdevice based on a determination by the recipient device that thealerting message has been received at least a predetermined number oftimes.
 10. The apparatus of claim 9, wherein: the alerting message isnot renderable by the recipient device when a relative motion isindicative of the recipient device moving away from the targetgeographic region.
 11. The apparatus of claim 9, wherein: the alertingmessage is not retransmittable by the recipient device when the alertingmessage has not been received at least a predetermined number of times.12. The apparatus of claim 9, the operations further comprising:identifying a plurality of target geographic regions for receipt of arespective plurality of alerting messages pertaining to the emergentsituation; determining respective content for each of the plurality ofalerting messages; and providing the plurality of alerting messages,each of the plurality of alerting message comprising: an indication of arespective target geographic region; and an indication of respectivecontent.
 13. The apparatus of claim 9, wherein: the alerting messagecomprises a plurality of content portions; each of the plurality ofcontent portions comprises content tailored to a respective targetgeographic region; tailored content is renderable by a recipient of thealerting message when a location at which the alerting message isreceived is within a respective target geographic region for thetailored content; and tailored content is not renderable by a recipientof the alerting message when a location at which the alerting message isreceived is not within a respective target geographic region for thetailored content.
 14. The apparatus of claim 9, wherein: the alertingmessage further comprises a behavior routine; and the behavior routineis invokable by a recipient of the alerting message when the alertingmessage is renderable by the recipient.
 15. The apparatus of claim 9,wherein content of the alerting message is determined at a time when theindication of the emergent situation is received.
 16. The apparatus ofclaim 9, wherein: the alerting message is retransmittable by a recipientof the alerting message when the alerting message has been received atleast a predetermined number of times and the alerting message was notsent from a location closer than a minimum distance from the location atwhich the alerting message was received; and the alerting message is notretransmittable by a recipient of the alerting message when the alertingmessage has not been received at least a predetermined number of timesor the alerting message was sent from a location closer than a minimumdistance from the location at which the alerting message was received.17. An apparatus comprising: a processor; and memory coupled to theprocessor, the memory comprising executable instructions that whenexecuted by the processor cause the processor to effectuate operationscomprising: receiving a signal comprising: a plurality of messages; anda plurality of target distribution regions, wherein each message of theplurality of messages is associated with a target distribution region ofthe plurality of target distribution regions; comparing a location atwhich the signal is received with the plurality of target distributionregions; and upon a determination that the location at which the signalis received is within one of the plurality of target distributionregions, rendering a message of the plurality of messages associatedwith the target distribution region at which the signal is received. 18.The apparatus of claim 17, wherein: at least one message of theplurality of messages comprises a plurality of portions; and eachportion of the plurality of portions is associated with a respectivetarget distribution region.
 19. The apparatus of claim 17, wherein: atleast one message of the plurality of messages comprises a plurality ofportions; and each portion of the plurality of portions is associatedwith a respective message.
 20. The apparatus of claim 17, wherein: atleast one message of the plurality of messages a plurality of contentportions; each of the plurality of content portions comprises contenttailored to a respective target geographic region; tailored content isrenderable by a recipient device of an alerting message when a locationat which the alerting message is received is within a respective targetgeographic region for the tailored content; and tailored content is notrenderable by a recipient device of an alerting message when a locationat which the alerting message is received is not within a respectivetarget geographic region for the tailored content.